JP2803796B2 - Load sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The disclosed technology is a sensor structure technology capable of measuring a compressive load or a tensile load applied to an object by distorting the object and performing load electric conversion. Belongs to the field. <Summary of the Summary> Thus, the invention of this application converts the change in force applied to an object into an electric signal to measure the amount thereof, and uses the piezo effect to use it as a means for controlling, The present invention relates to a pn junction type load sensor in which a p-type element and an n-type element formed of a silicon semiconductor are stacked in a stack and connected to a measurement circuit by a lead wire via a silver paste or the like. One or both of the element and the n-type element are formed by combining single crystal silicon and amorphous silicon such as hydrogenated microcrystal silicon so that at least one of them is formed from amorphous silicon. A load is linearly applied to a substantially central portion thereof, and an amorphous silicon of an i-type element is interposed between a p-type element and an n-type element. An invention relating to a good load sensor of detection characteristics you. <Conventional technology> As is well known, the progress of science and technology has been remarkable in recent years,
The results are not only put to practical use, but also fed back to further research and development, and there is a close relationship between them to promote technology development, for example, various devices and equipment A technique of electrically converting a strain caused by a load applied to a substrate to quantitatively process data has been regarded as extremely important. Thus, a load sensor used as a gauge for converting a force and an electric signal for strain detection is, for example, a metal foil or the like used for a gauge of a load cell, and a resistance change due to physical or mechanical strain. Was converted to an electrical signal. Incidentally, the load sensor according to the above-mentioned technology is remarkably large in recent years with the miniaturization of various devices, and furthermore, the applied voltage and current are large, the data processing becomes large, and the processing speed is slow. There was a disadvantage that the cost was high. To cope with this, for example, as described in Kiyoshi Takahashi, "Semiconductor Engineering" (published by Morikita Publishing, September 1975), a load sensor of a strain gauge utilizing the piezo effect of a silicon semiconductor. Has been developed and put into practical use. As is well known, as shown in FIG. 17, n formed by a silicon semiconductor made of single crystal silicon is used.
The p-type element 1 and the p-type element 2 are laminated to form a pn junction type load sensor 3, and a state change due to an applied load of the bonding layer is physically converted into an electric signal, for example, as shown in FIG. Load F perpendicular to the joint surface
19, and as shown in FIG. 19, the beam 4 'is set on the beam 4' to detect a strain parallel to both surfaces due to an applied load F. Further, as shown in FIG. The 4 "torsion detector is used as a gauge for periodically detecting the strain in the shear direction. Even though the size of these elements is extremely small, the advantage that the resistance change to the strain is extremely large is fully utilized. <Problems to be Solved by the Invention> However, in each of the above-described load sensors using a silicon semiconductor p-type element and an n-type element using a single crystal silicon material as a conventional technique at the time of the invention of this application, The element has a small area of about 1 mm square, and the pressure receiving area is relatively small, so the power supply current required for measurement is large. Therefore, there is a disadvantage that the power consumption is large, there is a disadvantage that the range of application as a load sensor is narrow, and there is also a disadvantage that manufacturing a silicon semiconductor as a material significantly increases the cost. Purpose> The purpose of the invention of this application is to solve the problems of the gauge element made of single crystal silicon based on the above-described conventional technology, and to fully utilize the applied load of the pn junction and the advantages of the electric signal conversion function. Uses the ease of manufacturing p-type and n-type devices through high-frequency glow discharge decomposition of amorphous silicon, obtains a pn junction with a large junction area, requires low operating power, and achieves large voltage and current changes. The aim is to provide an excellent load sensor that can be used at low cost to expand the range of application and that benefits measurement technology applications in various industries. <Means and Actions for Solving the Problems> In order to solve the above-mentioned problems, the configuration of the invention of the present application having the above-mentioned claims in accordance with the above-mentioned objects is as follows. Element or n-type element,
Alternatively, of at least one of the combinations of single crystal silicon and amorphous silicon, amorphous silicon is converted into a silicon semiconductor using hydrogenated microcrystal silicon or the like, and a load is linearly applied to the amorphous silicon at a substantially central portion thereof. Further, an amorphous silicon i-type element for improving rectification of a pn junction, which is neither a p-type element nor an n-type element, is interposed between the p-type element and the n-type element. In addition, the application area is widened by increasing the junction area of the sensing part, and even if the power supply current is reduced, a sensitive and sufficient voltage change and current change can be obtained, and the power consumption is also reduced. It is a technical measure that has a small number, has excellent detection characteristics, can be manufactured at low cost, and can reliably perform measurement. <Example> Next, an example of the invention of this application will be described with reference to FIGS. 17 to 20 are described using the same reference numerals. 10 to 15 schematically show the load sensor main bodies 31 to 36 of the invention of the present application, in which the white portion is an element made of single crystal silicon and has an ascending diagonal line. Is an n-type element 1 'of a silicon semiconductor formed of amorphous silicon such as hydrogenated microcrystalline silicon, and an element having a diagonal line descending to the right is a silicon semiconductor p-type of amorphous silicon such as hydrogenated microcrystalline silicon. Mold element 2 '
Therefore, the load sensor 31 shown in FIG.
Is a pn junction of an n-type element 1 'and a silicon semiconductor p-type element 2 made of single-crystal silicon. The load sensor 32 shown in FIG. 11 is such that the n-type element 1 is made of a single-crystal silicon semiconductor. , P-type element 2 'is a pn junction made of amorphous silicon such as hydrogenated microcrystal silicon, and the load sensor body 33 shown in FIG.
Each of the mold elements 2 'is a pn junction made of a silicon semiconductor of amorphous silicon such as hydrogenated microcrystal silicon. Thus, in another embodiment of the present application, the number of diameters of 10 within the amorphous silicon is between the p-type element and the n-type element.
An amorphous silicon i-type element 5 having a single crystal silicon having a thickness of about 200 angstroms and having excellent control characteristics is interposed to form a pin junction layer. In the load sensor body 34 shown in FIG. 1 'is an amorphous silicon silicon semiconductor, a p-type element is a silicon semiconductor made of single crystal silicon, and in the load sensor body 35 shown in FIG. 14, an n-type element 1 is a single crystal silicon semiconductor. The p-type element 2 'is a pin junction layer so that it is a silicon semiconductor of amorphous silicon. In the load sensor body 36 shown in FIG. 15, both the n-type element 1' and the p-type element 2 'are amorphous. It is formed on a pin junction layer made of a silicon semiconductor of silicon. In the invention of this application, as shown in FIG. 16, as described above, the hydrogenated microcrystalline silicon 6 'can be considered as a part of a state within the range of the hydrogenated amorphous silicon 6. The function is expected to be equivalent to the characteristics of amorphous silicon, and therefore, in the present invention, hydrogenated microcrystalline silicon is hydrogenated amorphous silicon, that is, microcrystalline silicon is equivalent to amorphous silicon. Is considered. The amorphous silicon element, the microcrystal silicon element, and the i-type element in the invention of this application can be formed to a very small thickness of about 1 μm by the technology developed so far. , The p-type element 2 ′, and the middle i-type element 6
m, whereas the conventional n-type element 1 and p-type element 2 of silicon semiconductor made of single crystal silicon have a thickness of 0.5 m.
Because of the thickness of m, the load sensor bodies 31, 32, 34, and 35 shown in FIGS. 10, 11, 13, and 14 have thicknesses of the p-type element 2 and the n-type element 1 made of a silicon semiconductor of almost single crystal silicon. 0.5 mm, which is almost the same as
The load sensors 33 and 36 shown in FIGS. 2 and 15 have a micronized thickness of 2 μm to 3 μm, and the load sensors of an n-type element 1 and a p-type element 2 made of a monocrystalline silicon semiconductor shown in FIG. Compared to the thickness of the main body 3 of 1 mm, it is extremely thin, and therefore, its thickness is almost zero in comparison with its pn junction area, so that the change of the current-voltage characteristic with respect to the force can be extremely sensitively improved. Therefore, the load sensor 7 using the load sensor body 31 shown in FIG. 10 as the most basic and simple model will be described with reference to FIGS. 1 to 6. The type element 1 'and the p-type element 2 of single crystal silicon are used as a pn junction type load sensor main body 31, and the n-type element 1' and the p-type element 2 are used as gold ohmic electrodes containing about 1% of antimony. The thin films 8 and 8 are vapor-deposited, and the lead wires 10 of the conductive wires are respectively connected to the vapor-deposited thin films 8 of gold via silver paste 9 and are connected to a constant voltage power supply 12 through an ammeter 11 as shown in FIG. Connect, or
As shown in FIG. 6, a constant current power supply 12 'is connected via a voltmeter 11'.
Are connected in series. Then, the load sensor 7 is placed on the base 4 via the electrically insulating glass plate 13 in this manner, and further, the glass plate 13 'is placed thereon to apply a linear load F to the bar 13 ". The data of the substrate of the p-type element 2 and the data of the thin film of the n-type element 1 'are as shown in Tables 1 and 2 below. The bonding area is a rectangular shape of 0.8 cm ^2. The current-voltage characteristics were tested by changing the load F in the direction perpendicular to the bonding surface by using the setting device shown in FIGS. In the forward characteristic shown in FIG. 7 and the reverse characteristic shown in FIG. 8, the current increases at a constant voltage as the load F increases, as shown in the graph of FIG. It was also found that the voltage decreased even with a constant current, and the characteristics themselves were substantially the same as those of the n-type element 1 and the p-type element 2 of the conventional single crystal silicon semiconductor. . As shown in FIG. 9, the data obtained by measuring the voltage change with respect to the load by the apparatus shown in FIG. 5 shows that the characteristics in the direction indicated by white circles show hysteresis almost matching the characteristics in the direction indicated by black circles. It has also been found that it exhibits excellent characteristics. As for the apparatus, as shown in FIG. 3, the application of a load F in the direction perpendicular to the joining surface is extremely large, so that a large applied pressure is required for the applied load over the entire surface. In contrast to the fact that the application element is difficult to form by the application, the bar 13 ″ is a kind of linear load because of its circular cross section, so that the stability of the application of the load and the application of the measurement can be obtained. It is needless to say that the embodiment of the present invention is not limited to the above-described embodiments. For example, it is possible to use amorphous silicon other than hydrogenated microcrystalline silicon for the n-type element and the p-type element. Further, the present invention is applicable not only to detection of strain perpendicular to the joint surface but also to detection of strain parallel to the joint surface and shear strain to the joint surface. Therefore, the present invention can be applied to various load testing devices, detecting devices, and measuring devices in actual devices. According to the invention, when the applied load is converted into an electric signal to measure the strain or the applied load, the load sensor body is significantly reduced in size as a load sensor, and not only the initial cost but also the power consumption is reduced. It has the excellent effect that running costs can be kept low because it is small, and it is also a load sensor such as a conventional metal foil strain gauge or a conventional strain gauge made of a single crystal silicon silicon semiconductor. The sensitivity is tens of times to hundreds of times more sensitive than that of, and even if the current from the power supply is small, a sufficient voltage change can be obtained, and more precise and precise measurement can be performed. Therefore, it has an excellent effect that it has a very high contribution to various industrial fields where load and strain measurement must be performed. Since the silicon n-type element and p-type element can be formed into a thin film through high-frequency glow discharge decomposition, the thickness is small and the bonding area is wide, so that a wide load can be applied to the sensing part. An excellent effect is obtained in that a sensor body can be obtained and a sensitive and high load sensor can be provided as described above, and as described above, an amorphous silicon thin film element obtained by high-frequency glow discharge decomposition can be obtained. As a result, mass production is possible from conventional single crystal silicon semiconductors, etc. To be performed easily load sensor obtained at a relatively low cost, excellent effect that the application range is also enlarged are obtained. Furthermore, since the semiconductor element of i-type amorphous silicon is interposed between the p-type element and the n-type element, the rectifying property of the pn junction is improved, and a load sensor with good detection characteristics can be provided. The effect is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 16 are explanatory diagrams of an embodiment of the invention of the present application,
1 is a schematic perspective view of a load sensor according to one embodiment, FIG. 2 is a side view of the load sensor, FIG. 3 is a schematic perspective view of a load detection mode, FIG. 4 is a schematic front view of the load sensor, and FIG. FIG. 6 is a schematic front view of a measurement device for measuring a change in current with respect to the applied load, FIG. 6 is a schematic front view of the measurement when the voltage is changed with respect to the magnitude of the applied load, and FIG. Directional characteristic graph, FIG. 8 is the same reverse characteristic graph, FIG. 9 is a hysteresis graph of load and voltage change at constant current, FIGS. 10 to 15 are schematic front views of each aspect of the load sensor body, FIG. 16 is a schematic diagram showing the correspondence relationship between amorphous silicon and microcrystalline silicon, FIG. 17 is a schematic front view of a load sensor body based on the prior art, and FIGS. It is a correspondence schematic diagram. 2 ': p-type element, 1': n-type element, 10: lead wire, 7: load sensor, 5: i-type element, F: load

Claims (1)

(57) [Claims] In a pn junction type load sensor in which a p-type element and an n-type element formed of a silicon semiconductor are stacked and connected to respective lead wires, at least one of the silicon semiconductors forming the p-type element and the n-type element A load sensor comprising amorphous silicon of monocrystalline silicon and amorphous silicon, wherein the amorphous silicon is hydrogenated microcrystalline silicon, and a linear load is applied to the amorphous silicon substantially at a central portion thereof. 2. 2. The load sensor according to claim 1, wherein an intrinsic semiconductor element made of amorphous silicon is interposed between the p-type element and the n-type element.